1. Field of the Invention
The present invention relates to an image reading apparatus in which read data between a plurality of image reading sensor units are combined. In particular, the present invention relates to an image reading apparatus in which a plurality of image reading sensor units are arranged in a zigzag manner.
2. Related Background Art
With respect to conventional technologies, a conventional technology for correcting the amount of shift in a direction orthogonal to an arrangement direction of sensor arrays arranged in a zigzag manner is disclosed in JP 62-258553 A. According to this technology, storing means having a data storage region corresponding to each of the sensor arrays is used and read data is stored in a storage region designated by an address determined based on the amount of shift. Circular addressing is used for memory saving.
However, in the conventional technology, the correction is performed in a unit of line for each of the sensor arrays arranged in the zigzag manner, and hence no adjustment is performed based on a distance equal to or shorter than a distance between lines. In a case of a color reading apparatus for successively reading respective red, green, and blue colors in each line while a document is continuously conveyed, only the adjustment performed merely in a unit of line as in the conventional technology may cause a color shift. In other words, when the continuously conveyed document is to be subjected to color reading, the red, green, and blue colors are read for each line in order. Therefore, a read timing is shifted among the red, green, and blue colors. In addition, data is read at different timings among the respective sensor arrays. Thus, even when the adjustment is performed for each line, a read color may be different from a corresponding color of the document, and hence the accurate color of the document cannot be reproduced.